Great excitement prevailed at Nashville, Tenn., in consequence of the rebel General Forrest, with a force of over three thousand mounted men, having made a descent upon the railroad between that place and Bridgeport. Skirmishing occurred in the neighborhood of Murfreesboro, a railroad bridge at a point south  of that place being destroyed by the rebels.--A band of guerrillas, under the chief White, of Loudon County, Va., made a raid into Langley, six miles above Georgetown, D. C., driving in the pickets, without any casualty.--Colonel Cloud, in a message to General Blunt, dated at Fort Smith, Ark., said he had just returned from a raid in the Arkansas Valley. Near Dardanelles he was joined by three hundred “mounted Feds,” as the Union Arkansians are called, and with them and his own force routed the rebels, one thousand strong. They fled in confusion leaving tents, cooking utensils, wheat, flour, salt, sugar, and two hundred head of beef cattle behind. They reported as they ran that “Old Blunt, with his whole army, was after them.” Several hundred Union men offered their services as a home guard regiment. Colonel Cloud authorized them to enrol and offer their services to the Military Governor, when appointed. He left garrisons there and at Clarksville.--the batteries on Lookout Mountain, and at points all along the rebel lines, opened fire upon Chattanooga. The Unionists under Rosecrans, replied from their works on Moccasin Point, the Star Fort, and other works. The Tennessee River rose rapidly during the day.--A party of Captain Bean's cavalry on a scouting expedition near Harper's Ferry, Va., encountered a number of rebel cavalry belonging to the command of Colonel Imboden. A skirmish ensued, when the Union forces were repulsed, with a loss of one killed, three wounded, and ten captured. Two of the Unionists cut their way out and returned to camp, although severely wounded.